/*
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.l2j.gameserver.skills;

import javolution.util.FastList;
import net.sf.l2j.gameserver.skills.funcs.Func;


/**
 * A calculator is created to manage and dynamically calculate the effect of a character property (ex : MAX_HP, REGENERATE_HP_RATE...).
 * In fact, each calculator is a table of Func object in which each Func represents a mathematic function : <BR><BR>
 *
 * FuncAtkAccuracy -> Math.sqrt(_player.getDEX())*6+_player.getLevel()<BR><BR>
 *
 * When the calc method of a calculator is launched, each mathematic function is called according to its priority <B>_order</B>.
 * Indeed, Func with lowest priority order is executed first and Funcs with the same order are executed in unspecified order.
 * The result of the calculation is stored in the value property of an Env class instance.<BR><BR>
 *
 * Method addFunc and removeFunc permit to add and remove a Func object from a Calculator.<BR><BR>
 *
 */

public final class Calculator
{
    /** Empty Func table definition */
	private static final Func[] _emptyFuncs = new Func[0];

	/** Table of Func object */
	private Func[] _functions;
	/**
	 * Constructor of Calculator (Init value : emptyFuncs).<BR><BR>
	 */
	public Calculator()
	{
		_functions = _emptyFuncs;
	}

	/**
	 * Constructor of Calculator (Init value : Calculator c).<BR><BR>
	 */
	public Calculator(Calculator c)
	{
		_functions = c._functions;
	}


	/**
	 * Check if 2 calculators are equals.<BR><BR>
	 */
	public static boolean equalsCals(Calculator c1, Calculator c2)
	{
		if (c1 == c2)
			return true;

		if (c1 == null || c2 == null)
			return false;

		Func[] funcs1 = c1._functions;
		Func[] funcs2 = c2._functions;

		if (funcs1 == funcs2)
			return true;

		if (funcs1.length != funcs2.length)
			return false;

		if (funcs1.length == 0)
			return true;

		for (int i=0; i < funcs1.length; i++)
		{
			if (funcs1[i] != funcs2[i])
				return false;
		}
		return true;

	}


	/**
	 * Return the number of Funcs in the Calculator.<BR><BR>
	 */
	public int size()
	{
		return _functions.length;
	}


	/**
	 * Add a Func to the Calculator.<BR><BR>
	 */
	public synchronized void addFunc(Func f)
	{
		Func[] funcs = _functions;
		Func[] tmp = new Func[funcs.length+1];

		final int order = f.order;
		int i;

		for (i=0; i < funcs.length && order >= funcs[i].order; i++)
			tmp[i] = funcs[i];

		tmp[i] = f;

		for (; i < funcs.length; i++)
			tmp[i+1] = funcs[i];

		_functions = tmp;
	}


	/**
	 * Remove a Func from the Calculator.<BR><BR>
	 */
	public synchronized void removeFunc(Func f)
	{
		Func[] funcs = _functions;
		Func[] tmp = new Func[funcs.length-1];

		int i;

		for (i=0; i < funcs.length && f != funcs[i]; i++)
			tmp[i] = funcs[i];

		if (i == funcs.length)
			return;

		for (i++; i < funcs.length; i++)
			tmp[i-1] = funcs[i];

		if (tmp.length == 0)
			_functions = _emptyFuncs;
		else
			_functions = tmp;

	}

	/**
	 * Remove each Func with the specified owner of the Calculator.<BR><BR>
	 */
	public synchronized FastList<Stats> removeOwner(Object owner)
	{
		FastList<Stats> modifiedStats = new FastList<Stats>();

		for (Func func: _functions)
		{
			if (func.funcOwner == owner)
			{
				modifiedStats.add(func.stat);
				removeFunc(func);
			}
		}
		return modifiedStats;

	}


	/**
	 * Run each Func of the Calculator.<BR><BR>
	 */
	public void calc(Env env)
	{
		for (Func func: _functions)
			func.calc(env);
	}

}
